The present invention relates to a method and apparatus for remanufacturing process cartridges. More specifically, the invention relates to securing covers of process cartridges.
In the well-known process of electrophotographic printing, the charge retentive surface, typically known as a photoreceptor, is electrostatically charged, and then exposed to a light pattern of an original image to selectively discharge the surface in accordance therewith. The resulting pattern of charged and discharged areas on the photoreceptor form an electrostatic charge pattern, known as a latent image, conforming to the original image. The latent image is developed by contacting it with a finely divided electrostatically attractable powder known as xe2x80x9ctoner.xe2x80x9d Toner is held on the image areas by the electrostatic charge on the photoreceptor surface. Thus, a toner image is produced in conformity with a light image of the original being reproduced. The toner image may then be transferred to a substrate or support member (e.g., paper), and the image affixed thereto to form a permanent record of the image to be reproduced. Subsequent to development, excess toner left on the charge retentive surface is cleaned from the surface. The process is useful for light lens copying from an original or printing electronically generated or stored originals such as with a raster output scanner (ROS), where a charged surface may be imagewise discharged in a variety of ways. In a printer, as the toner within the developer material is transferred to the photoreceptor and eventually to the copy paper, this used toner must be replaced. The printer thus includes a container or cartridge from which fresh toner is dispensed into the machine. To provide for a small, compact cartridge and to provide for a cartridge in which the cartridge may be easily removed, the cartridge typically has a compact shape.
Service costs represent a significant portion of the cost associated with operating a printing machine. Certain components represent those most likely to require service. By providing a method of easily replacing those certain components, the operator may replace those components himself, avoiding service technician labor costs.
These certain components are consolidated within a housing that may be easily replaced by the customer. This housing is typically called a customer replaceable unit (CRU). For example, in addition to toner, components that may be included in a CRU are the charging device (a corotron or a bias charge roll), and the photoreceptor.
A CRU may be changed several times during the life of a copy machine. While a few of the components within a CRU are consumed during the life of the CRU many of the components may be reused. Therefore, CRUs are now being frequently remanufactured rather than being made from all completely new components. The remanufacturing includes replacing spent components and inspecting all components that may wear. Worn components are replaced if so required.
Copy machines and printing machines include components that wear or become spent or consumed during normal use. For copying and printing machines such components that are consumed or become spent include developer material including toner and, if appropriate, carrier as well as the photoconductive member in the form of either a belt or a drum. Addition components may also wear during the life of the copying and printing machine. Such components include cleaning blades and brushes as well as charge corotrons and fuser rolls.
As mentioned above, to reduce service costs, improve copy quality and to improve the reliability and running time of copying and printing machines, certain components that wear, become consumed or are spent are grouped into a subassembly which may be readily replaced by a minimally trained operator. These groups of components are typically grouped into a housing which is easily insertable into the machine. These assemblies are typically called CRUs or process cartridges.
The housings in which the wear and spent components are placed to form the process cartridge typically are very durable and have a very long life. Since the process cartridge is replaced several times during the life of the machine, a large number of spent or consumed process cartridges accumulate during the life of machines, particularly those which have large quantities of machines manufactured.
During remanufacture, the process cartridges are disassembled and worn components replaced. To provide for replacement of the wear and consumable components, the housings of the process cartridges typically include upper and lower halves which are opened to install or replace components and closed after the components are replaced so the cartridge may function.
The upper and lower portions of the process cartridge housing must be securely fastened to each other. Several attempts have been made to join the upper and lower portions of a process cartridge. For example, the upper and lower portions of the cartridges may be sealed by an adhesive, for example, a glue. Also the upper and lower portions of the process cartridge may be tack welded to each other. The use of glues or tack welds in securing an upper and lower portion of a process cartridge may not provide for a secured joint. The upper and lower portions may break loose from each other when glue or tack weld is used.
Another common method of joining an upper and lower portion of a process cartridge is the use of screws, for example, self-tapping screws. Self-tapping screws have a series of problems. For example, when assembling the screws, particularly when using automated equipment, the equipment to tighten the screws may cause the screws to overtighten and strip. Further, with the use of screws, a screw can back out or become loose during shipment or use when vibration is present when the process cartridge is in use.
The following disclosures may be relevant to various aspects of the present invention:
U.S. Pat. No. 5,774,766 discloses a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus comprises an electrophotographic photosensitive drum, a development roller for developing a latent image formed on the electrophotographic photosensitive drum, a toner accommodating portion for accommodating toner to be used by the development roller for development, a photosensitive drum frame for supporting the electrophotographic photosensitive drum, a development frame including the toner accommodating portion, and a support frame including a first toner leakage preventing member positioned at one longitudinal end of the development roller and a second toner leakage preventing member positioned at the other longitudinal end of the development roller. The development frame and the support frame are rotatably connected about a positioning member and, in this connected state, a portion of the development frame is welded to a portion of the support frame so that the development frame and the support frame are joined together.
U.S. Pat. No. 5,729,795 discloses electrostatographic cartridges having a cartridge base, a toner hopper having a toner fill hole attached to the cartridge base, and a gear housing assembly which blocks access to the toner fill hole and which includes an interior gear housing component integral with the cartridge base are remanufactured by severing the interior gear housing component and then reattaching it to the cartridge base through the exterior gear housing component. Specifically, the one-piece interior gear housing component is severed so that it can be removed thereby providing unobstructed access to the original toner fill hole. Most preferably, the interior part of the gear housing is cut at a five degree angle relative to the cartridge base. The angular cut thereby ensures that the attachment bosses on the cartridge base which serve to couple the base to the toner cartridge cover are not damaged to an extent that would defeat their coupling function. Paired reattachment holes are formed in the interior and exterior gear housing components to allow them to be reattached to one another via screw and nut assemblies extending therethrough. The reattached interior and exterior gear housing components may then be connected to the cartridge base by screws supplied originally with the cartridge by original equipment manufacturer (OEM). In such a manner, fresh toner may be introduced into the toner hopper in a convenient fashion during the remanufacturing operation.
U.S. Pat. No. 5,619,309 discloses a process cartridge mountable to an image forming apparatus. The apparatus includes an image bearing member, process means acting on the image bearing member, and a plurality of frames for constituting a housing for the image bearing member and the process means. A projection is provided along an abutment portion of one of the frames to be welded.
U.S. Pat. No. 5,564,847 discloses a printer having a printhead which traverses laterally across a sheet-like print medium and which thereby defines a laterally-extending print zone across the print medium. A paper transport mechanism in the printer has drive rollers and associated pinch wheels to drive the print medium through the printer""s print zone. The paper transport mechanism further includes an upper print media guide and a lower print medium guide. The two print medium guides are shaped at their transverse ends to bow the transverse edges of the print medium downwardly to reduce its tendency to buckle upwardly into the printhead. In order to fit the upper print medium guide into the limited available space above the drive rollers, it is made of a lower molded portion for paper contact and an upper backing portion for rigidity. A pinch finger extends toward the printer""s print zone beyond the pinch wheels to establish a pinch point against the drive roller in near proximity to the print zone. To facilitate ejection of printed pages, the upper print medium guide is formed with a series of ribs which contact the paper. The ribs reduce friction and static buildup, and make it easier to push the paper from the paper transport mechanism.
U.S. Pat. No. 5,561,496 discloses an assembling method of an image forming apparatus for forming an image on a recording material includes preparing a frame, a feeding unit having a feeding roller, electrical component unit having electrical components and an outer cover; mounting the feeding unit and the electrical component unit to the frame from a position of the frame which takes a bottom position upon installation of the image forming apparatus; and then overturning of the frame; mounting the outer cover to the frame from a position which takes a top position upon installation of the frame.
U.S. Pat. No. 5,527,123 discloses a printer having a printhead which traverses laterally across a sheet-like print medium and which thereby defines a laterally-extending print zone across the print medium. A paper transport mechanism in the printer has drive rollers and associated pinch wheels to drive the print medium through the printer""s print zone. The paper transport mechanism further includes an upper print media guide and a lower print medium guide. The two print medium guides are shaped at their transverse ends to bow the transverse edges of the print medium downwardly to reduce its tendency to buckle upwardly into the printhead. In order to fit the upper print medium guide into the limited available space above the drive rollers, it is made of a lower molded portion for paper contact and an upper backing portion for rigidity. A pinch finger extends toward the printer""s print zone beyond the pinch wheels to establish a pinch point against the drive roller in near proximity to the print zone.
U.S. Pat. No. 5,311,265 discloses a toner loading system for use with reprographic machines which reduces powder clouding and minimizes toner spill during loading. A toner cartridge is mountable on a toner housing. The housing includes an opening sized to accept the cartridge. When in a raised position, the cartridge is on top of the housing. When in a lowered position, the cartridge is positioned within the housing through the opening. A removable seal on the bottom of the cartridge includes a long pull tab which can be grasped from above the housing, when the cartridge is lowered, to allow removal of the seal and allow flow of toner from the cartridge to the housing while the cartridge is extended substantially or completely within the housing, thus reducing powder clouding, providing more even toner flow, and reducing mess or spillage. The reduced powder clouding is due to a substantially reduced height from which the toner has to fall when being loaded into the housing.
U.S. Pat. No. 5,296,902 discloses an apparatus and method for providing a removable closure seal between the toner hopper and the toner feed roller compartment of a toner cartridge assembly used in printers, copy machines and facsimile machines. The seal prevents toner from leaking from the toner hopper into the feed roller compartment during shipping and handling. In one embodiment, the seal has a slotted seal insert placed over the passage between the hopper and roller compartment. A removable tape closes the slot. In another embodiment, a slotted seal insert is slid between grooves in the toner cartridge assembly into position between the hopper and feed roller compartment. The insert is attached to the cartridge assembly by glue, tape, or other adhesive. An insert tool is used to facilitate this attachment. A reusable, removable closure seal is slid between the grooves to close the slot. The closure seal may have a metal spine to increase its rigidity. A crush-resistant velvet material with a foam backing is used to improve the seals at the ends of the feed roller compartment.
As will be seen from an examination of the prior art, it is desirable to provide an electrostatographic copying system with a toner cartridge having a resealing system that is simple, reliable, and inexpensive. The present invention is directed to overcoming at least some of the aforementioned problems.
In accordance with one aspect of the present invention, there is provided a process cartridge for use in a printing machine. The process cartridge includes a first housing portion including a first housing attachment surface and a second housing portion including a second housing attachment surface. At least a portion of the second housing attachment surface is associated with at least a portion of the first housing attachment surface. The process cartridge further includes a plurality of rivets. Each of the plurality of rivets includes a retaining portion thereof. At least one of the first housing portion and the second housing portion define an aperture for passage of the retaining portion of at least one of the rivets therethrough. The other of at least one of the first housing portion and the second housing portion define a cavity for receiving the retaining portion of the at least one rivet. The portion of the housing defining the cavity being interferencely fitted to the retaining portion of the at least one rivet.
In accordance with yet another aspect of the present invention, there is provided an electrophotographic printing machine of the type including a process cartridge. The process cartridge includes a first housing portion including a first housing attachment surface and a second housing portion including a second housing attachment surface. At least a portion of the second housing attachment surface is associated with at least a portion of the first housing attachment surface. The process cartridge further includes a plurality of rivets. Each of the plurality of rivets includes a retaining portion thereof. At least one of the first housing portion and the second housing portion define an aperture for passage of the retaining portion of at least one of the rivets therethrough. The other of at least one of the first housing portion and the second housing portion define a cavity for receiving the retaining portion of the at least one rivet. The portion of the housing defining the cavity being interferencely fitted to the retaining portion of the at least one rivet.
In accordance with another aspect of the present invention, there is provided a method for manufacturing process cartridge for use in a printing machine. The method includes the steps of providing a plurality of rivets each of the rivets having a head and a retaining portion, providing a first portion of a process cartridge, the first portion defining an aperture, providing a second portion of a process cartridge, the first portion defining a cavity, passing the retaining portion one of the plurality of rivets through the aperture, inserting the retaining portion of one of the plurality of rivets into the cavity, seating the head of the one of the plurality of rivets against the first portion of the process cartridge, and securing the retaining portion of one of the plurality of rivets to the second portion of a process cartridge, thereby securing the first portion of a process cartridge to the second portion of the process cartridge.
In accordance with yet another aspect of the present invention, there is provided a method for remanufacturing a process cartridge utilizing a plurality of rivets for assembly thereof. The method includes the steps of disassembling the used process cartridge, inspecting internal components of the process cartridge, performing at least one of repairing and replacing at least one of the internal components of the process cartridge, assembling the internal components of the process cartridge into at least one of a first housing portion and a second housing portion, tack welding the first housing portion of the process cartridge to the second housing portion of the process cartridge, testing the process cartridge, breaking the tack welds if the process cartridge fails the testing step, performing at least one of repairing and replacing any components that fail at the testing step, retack welding the first housing portion of the process cartridge to the second housing portion of the process cartridge if the breaking step is required, repeating the testing step, the breaking step, the performing step and the retack welding step as required, passing the retaining portion one of said plurality of rivets through the aperture, inserting the retaining portion of one of said plurality of rivets into the cavity, seating the head of the one of said plurality of rivets against the first housing portion of the process cartridge; and securing the retaining portion of one of said plurality of rivets to the second housing portion of the process cartridge, thereby securing the first portion of the process cartridge to the second housing portion of the process cartridge.
In accordance with yet another aspect of the present invention, there is provided a rivet for use in a process cartridge for use in a printing machine. The rivet includes a body, a head attached to one end of the body and a retaining portion attached to the body and spaced from the retaining portion. The head has a shape selected to inhibit the removal of the rivet from the process cartridge by rotating the rivet with respect to the cartridge.